I'm trying to figure out how the mechanics of holographic radar work. AFAIK there is a continuous 3d transmission signal (a dome-shaped antenna?) But because there isn't a direction or time-domain, how do we observe the return signal from objects and locate them? Is there any reference material / books on how this works?
It looks like any other modern signal processed multi-beam radar system - I think the "holographic" probably has more to do with their marketing dept than anything to do with holograms.
With phased array radars, instead of having a single rotating dish which transmits in a single direction and listens for a return form that direction, you have a series of fixed transmitters and receivers which broadcast and listen continuously. By measuring the the time a signal received at different receivers you can work out the angle it came from. In practice it's complicated, especially in environments with lots of background reflections - but with enough software it's doable.